re PR libstdc++/12875 (Weird behaviour in basic_filebuf::setbuf())

re PR libstdc++/12875 (Weird behaviour in basic_filebuf::setbuf())

2003-11-11  Paolo Carlini  <pcarlini@suse.de>

	PR libstdc++/12875
	* include/bits/fstream.tcc (setbuf): Don't do anything
	after open(), in particular don't discard data.
	(_M_allocate_internal_buffer): Tweak to not allocate memory
	in case the buffer is provided by the user via setbuf.
	* include/ext/stdio_filebuf.h: Tweak comment.
	* testsuite/27_io/basic_filebuf/setbuf/char/12875-1.cc: New.
	* testsuite/27_io/basic_filebuf/setbuf/char/12875-2.cc: Likewise.
	* testsuite/27_io/basic_filebuf/setbuf/char/2.cc: Tweak, now
	setbuf does nothing after open().
	* testsuite/27_io/basic_filebuf/setbuf/char/3.cc: Likewise.

From-SVN: r73477